1. Field of the Invention
The present invention relates to a method of converting the size of an image, i.e., resolution of an image, and more specifically, to a method of reducing or enlarging the size of an image using integer discrete cosine transform (Integer DCT) coefficients.
2. Background of the Related Art
Different communication networks are merged with one another in the present communication environments using broadband convergence networks (BcN), i.e., core networks capable of providing services such as connection of wired and wireless communications, merger of broadcasting and communication networks, IP convergence using IP networks, and the like, and such a trend will be further accelerated in the future. Along with the trend of digital convergence in heterogeneous communication network environments, researches on universal media communications are actively in progress recently. Since the types of multimedia terminals used in a variety of communication networks are more and more diversified, techniques for converting the size of an image are developed in various ways to reasonably harmonize different networks and different multimedia terminals with one another.
Among the techniques for converting the size of an image, a method using real-number discrete cosine transform (DCT) coefficients shows superior performance. Since the real-number DCT coefficients are used in conversion techniques employing a moving picture codec such as MPEG-1, MPEG-2, MPEG-4, H.261, H.263, or H.26L, the techniques using the real-number DCT coefficients are advantageously compatible with existing moving picture codecs.
However, there is a problem in that conventional techniques for converting the size of an image using real-number DCT coefficients cannot be applied, as it is, to a H.264/AVC codec that generates integer DCT coefficients using an integer discrete cosine transform (integer DCT) technique in a transforming procedure of the codec. Furthermore, since conventional techniques for converting the size of an image using real-number DCT coefficients perform real-number operations, complexity is so high in manufacturing hardware that they are not easy to implement.